yet again: Nanotyrannus or Dakotaraptor?

[JoeS]

Hi all, I posted this tooth for ID a while back. Conclusion was that it could be a Dakotaraptor, maybe, maybe. Since then I am going back and forth on the ID, basically on a daily basis
So I decided to take more & new images, measure it thoroughly, put it up again, and kindly ask for your help.
It was found in the Hell Creek Fm, Powder River Co., Montana.
Measurements are: CH: 2.08cm  CBL: 0.8cm  CBW: 0.42cm
Serration count per 5mm is mesial 24 and distal 18.

What makes it hard for me to judge: the shape of denticles is between round and chisel (?), the tiny mesial denticles, and the position of the carinae. Lowest part of the mesial carina is sheared off, but I would not expect a twist - looking closely it would end either half way or 1/3 from base.

Any help is highly appreciated!

 

[Pemphix]

Nevertheless what it is - it's a nice piece for sure !  

 

[Troodon]

This one is quite easy to assign it's definitely a Nano.  Dakotaraptor teeth do not have a lingual twist to the mesial carina its straight.  That means the cross section at the base is more rectangular than almond shape.

 

This might help future ones

 

[JoeS]

I see, thanks! Could the displacement of the carina be a variation due to the position of the tooth? Though it is not following the tooth straight down it is straight in itself.

[JoeS]

16 minutes ago, Pemphix said:

Nevertheless what it is - it's a nice piece for sure !  

 

thanks, it is indeed one of my faves - no matter the ID

[Troodon]

4 hours ago, JoeS said:

I see, thanks! Could the displacement of the carina be a variation due to the position of the tooth? Though it is not following the tooth straight down it is straight in itself.

Dromaeosaurids teeth from the HC are very compressed and although some variations exist to the carina not to the extent of your tooth.  Its classic Nano with the pinch at the base.  Base cross-sections of DR are almond shape not rectangular.

 

It's one of the nicest I've seen, those serrations are stunning, nice photos.

[JoeS]

Thank you very much for your input, as always
Could one make an educated guess where in the jaw this tooth would be placed?

[Troodon]

It looks like an anterior tooth probably from the dentary but not sure.